I have 9 month old twins and a 21 month old toddler (exactly a year apart). I usually use my double and wear someone, so that's what I would suggest for you--a triple and wearing someone. Seriously, my double and my Beco are my #1 most valuable parenting tools. That said, I do have a triple. It's a beast to push, and that's why I can't imagine pushing a quad, but sometimes it's nice to have. I bought a triple Mountain Buggy on Craigslist for $100. Steal. All it needed was air in the tires and a date with a scrub brush and the water hose. I highly suggest you start watching your Craigslist. Mine (Houston) currently has a triple Baby Jogger and a triple Runabout listed. OR, my other favorite option, if you think you could your new one until he/she can sit up steadily, is the Choo Choo wagon. We LOVE ours. You can add a 4th "car" to it easily enough if you want a quad. Way cheaper than strollers and great for the neighborhood or zoo.

Here's a pic

I bought mine on the Step2 website.

HTH!

__________________~Erin~
busy mommy to one five-year-old and two four-year-olds